New car smell reaches toxic levels on hot days, researchers find
July 2024, phys.org
Data from several hot summer days, with outside air temperatures of 25.3 °C – 46.1 °C (77.5 °F – 115 °F), showed high levels of formaldehyde, acetaldehyde, and hexaldehyde.The Chinese national concentration limit for formaldehyde in passenger vehicle cabins is 100 μg/m3. The authors found levels in the experimental car sometimes exceeding 200 μg/m3. The national limit for acetaldehyde is 50 μg/m3. Levels in the experimental car could reach 140 μg/m3.
Acetaldehyde - ACGIH TLV C = 25 ppm; OSHA PEL TWA = 200 ppm; China National Limit 50 ug/m3; they found up to 140 ug/m3 which is 0.077ppmv (odor: pungent, fruity, suffocating, fresh, green)
Formaldehyde - ACGIH TLV C 0.3 ppm SEN; OSHA PEL TWA 0.75 ppm STEL = 2 ppm; China National Limit 100 μg/m3; they found above 200 ug/m3 which is 0.16ppmv (odor: pungent)
-Source: odor descriptions taken from AIHA Odor Thresholds for Chemicals with Established Health Standards, 2nd Edition
Surface temperature inside the car is a major modifier, but they don't mention anything about how the color of the car changes the temperature.
via School of Mechanical Engineering at Beijing Institute of Technology, Department of Environmental Health at Harvard School of Public Health, Department of Occupational and Environmental Health Sciences at Peking University School of Public Health: Zhang R. et al. Cabin air dynamics: Unraveling the patterns and drivers of volatile organic compound distribution in vehicles, PNAS Nexus (2024). DOI: 10.1093/pnasnexus/pgae243.
Image credit: AI Art - Cryogenic Hibernation Capsules - 2024
How personal care products affect indoor air quality
Oct 2024, phys.org
EPFL's Human-Oriented Built Environment Lab (HOBEL) at the Smart Living Lab in Fribourg, home to environmental chambers—unique experimental facilities resembling real indoor spaces that enable precise control and monitoring of indoor air quality.They wanted to mimic the use of these personal care products in an indoor environment. In one test, the researchers applied the products under typical conditions, while the air quality was carefully monitored. In another test, they did the same thing but also injected ozone, a reactive outdoor gas that occurs in European latitudes during the summer months.When ozone was introduced into the chamber, not only new VOCs but also new particles were generated, particularly from perfume and sprays, exceeding concentrations found in heavily polluted urban areas such as downtown Zurich."Some molecules 'nucleate'—in other words, they form new particles that can coagulate into larger ultrafine particles that can effectively deposit into our lungs," explains Licina. "In my opinion, we still don't fully understand the health effects of these pollutants, but they may be more harmful than we think, especially because they are applied close to our breathing zone. This is an area where new toxicological studies are needed.""I know this is difficult to hear, but we're going to have to reduce our reliance on these products, or if possible, replace them with more natural alternatives that contain fragrant compounds with low chemical reactivity. Another helpful measure would be to raise awareness of these issues among medical professionals and staff working with vulnerable groups, such as children and the elderly."
via Ecole Polytechnique Federale de Lausanne EPFL's Human-Oriented Built Environment Lab (HOBEL) at the Smart Living Lab in Fribourg: Tianren Wu et al, Indoor Emission, Oxidation, and New Particle Formation of Personal Care Product Related Volatile Organic Compounds, Environmental Science & Technology Letters (2024). DOI: 10.1021/acs.estlett.4c00353
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